Bug in sort 5.93 Ubuntu dapper

[Barry Finkel]

I have a file that does not sort properly in Ubuntu dapper.
The "man sort" page has at the bottom

     sort 5.93                     May 2006                  SORT(1)

zztydid% cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=6.06
DISTRIB_CODENAME=dapper
DISTRIB_DESCRIPTION="Ubuntu 6.06.2 LTS"
zztydid%

Here is the file; it contains no tabs nor other non-printing chars.
The sort utility appears to be ignoring blanks.

-----
XYZPRVIT aci
XYZPRVIT aci-win
XYZPUB am
XYZPUBIT anl
XYZPUB arg
XYZPUB bike
XYZPUBIT cis
XYZSCI cms
XYZPUB fab
XYZPUB fossil
XYZPUB industrial
XYZPRVIT it
XYZPUBIT lamp
XYZPUB lms     <=== does not sort correctly
XYZPRV telephone
XYZPUBIT wiki 
XYZPUBIT zimbra
-----

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Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 222, Room D209              Internet: address@hidden
Argonne, IL   60439-4828             IBMMAIL:  I1004994